There's a going theory out there that an undiscovered planet resides in our solar system somewhere beyond the orbit of Pluto. But NASA just finished an exhaustive survey — and it completely failed to turn up any evidence that "Planet X" exists. »3/10/14 11:39am 3/10/14 11:39am

We might just be on the verge of discovering a real Planet X, according to astronomers John Matese and Dan Whitmire. Subtle gravitational influences on comets way out in the Oort Cloud suggest there could be a huge gas giant affecting the other objects, and now NASA's Wise space telescope has given us the data to… »2/15/11 12:07pm 2/15/11 12:07pm

Top scientists are stepping forward to dispel rumors that the world is ending in 2012, combating a wave of Internet hysteria that coincides with the marketing frenzy for Roland Emmerich's rivers-of-schlock masterpiece 2012. One NASA scientist with a prominent website, David Morrison, says he used to get a question a… »10/20/09 9:30am 10/20/09 9:30am